Design and fabrication of photonic devices based on colloidal nanocrystals

Thanks to their low fabrication costs and the well established surface-functionalization techniques which allow their merging into a wide range of materials, wet-chemical synthesized colloidal nanocrystals are finding broad application in several fields, from pharmacology to cosmetics, food industry, textiles, optics and so on. In particular, semiconductor nanocrystals are widely exploited as quantum optical emitters, showing very high quantum yield (close to unity), stability, low tendency to photobleaching and possibility to be tuned from ultraviolet to infrared range. The realization of high performing photonic devices based on this class of emitters is therefore an extremely intriguing challenge; on the other hand, the best way to manipulate these emitters and integrate them in solid matrices, without dramatically decreasing their optical properties, is still under debate. Here we present a method for the fabrication of the main building blocks of photonic circuits by exploiting the localization of colloidal nanocrystals dispersed in polymeric matrices through lithographic techniques. The realization of waveguide structures, suspended stripes and photonic crystal nanocavities is shown as a demonstration of this approach.